In the case of fuel injection systems of internal combustion engines, it is known to use high-pressure pumps which apply a high pressure to the fuel to be injected. The fuel that has had such a high pressure applied to it is then injected by way of injectors into combustion chambers of the internal combustion engine. The high pressure of the fuel has a positive effect on the emissions values of the internal combustion engine, in particular for example CO2 emissions. It is therefore sought, in internal combustion engines which use gasoline as fuel, to achieve a pressure in the range from 200 bar-300 bar in the fuel, whereas in the case of diesel internal combustion engines, it is even the case that a pressure range of 2000 bar-3000 bar in the fuel is sought.
For applying the desired pressure to the fuel, the high-pressure pump normally has one piston which increases and decreases the volume of a pressure chamber and, during the decrease in volume, compresses the fuel in order to realize the desired pressure of the fuel. At the pressure chamber there are arranged valves, on the one hand an inlet valve which admits the fuel into the pressure chamber before the fuel is compressed, and on the other hand an outlet valve which discharges the compressed fuel from the pressure chamber into a line which then conducts the fuel, for example via a common rail, to the injectors.
Owing to the high pressures that can be achieved with the high-pressure pump, the closing elements of the valves are commonly of massive form, for example in the form of a ball valve or valve mushroom head, to name but two possible massive embodiments.
Such valve elements are duly highly robust with regard to the prevailing pressures in the high-pressure pump, but react relatively slowly to the forces acting on them.
Since high-pressure pumps commonly operate in the range of several thousand strokes per minute, it is however desirable, in particular, for the admission of the fuel into the pressure chamber to provide relatively fast-switching valves which can open and close quickly.
It is therefore known, for example, to use not ball valves or massive mushroom head closing elements but filigree valve lamellae which are deformable and which can open and close the respective valve by way of their deformation. Such an arrangement is described, for example, in EP 1 724 467 A1.
The valve lamella described in EP 1 724 467 A1 opens and closes owing to pressure differences in the fuel in a pressure chamber of the high-pressure pump. If the pressure in the pressure chamber is higher than that in the suction region arranged upstream of the pressure chamber, the valve lamella closes, whereas the valve lamella opens if the pressure in the suction region is higher than that in the pressure chamber. To hold the valve lamella open in targeted fashion, the valve lamella is, by a valve shank, forced into the open position even counter to a higher pressure in the pressure chamber than in the suction region, in order that the pump power of the high-pressure pump can thereby be set. If it is not sought to manually influence the pump power, the valve shank retracts and is not in contact with the valve lamella, such that the valve lamella can close owing to the pressure prevailing in the pressure chamber.
All known arrangements have the disadvantage that the operation thereof gives rise to a high level of noise generation during switching.